As the capacity showing is still 50GB, So enabling these registry keys, will ensure the size of respective OutlookOST.vhdx and OutlookSearchIndex.vhdx which gets saved in user profile to not go beyond 5 GB. Or am I missing something here?
We are using O365 with Windows Server 2016 and providing Hosted Shared Desktop to end users through Citrix (Virtual Apps and Desktops 1912).